Swiss Patents 337,653 and 339,735 propose a method of connecting wooden panels, for example, using the principle of tongue and groove joints, wherein oppositely disposed groove slits, shaped as segments of a circle, are cut in the connecting surfaces of the panels, and lamellar dowels, in the form of small elliptical plates, are inserted as connecting elements. The small elliptical plates have external dimensions matching those of the narrow slit-shaped grooves.
When making such dowel connections, very uniform application of glue on the side walls and bottom of the groove is necessary in order to produce an optimum glued joint. The application of the glue must also be metered very precisely so that no excess glue escapes at the ends of the workpieces to be joined, forming globs of glue that considerably complicate a precise fitting together of the workpieces and would have an adverse affect on appearance.
Known glue devices usually consist of a tube or compressible bottle onto which a tapered spout is threadably mounted, so that the glue can only be applied in beads. Known glue devices for flush application of glue, for example, on paper, are not suitable for such grooves because they cannot be used, for example, to coat the bottom of the groove in the corner areas inside the groove. In addition, these glue devices are too large as a rule to be inserted into a lamellar groove.